MacOS operating systems

I will try to. These would be 32 bit programs which might include those such as Microsoft Office or any non Apple program you have installed and which has not been upgraded to 64 bit versions. To check this out, you can go to About This Mac, below the Apple logo. This opens a window that has a System Report button. Click on it. On the next window, on the left side you will see a menu. Go down to Software and click on Applications. It may take a minute or two, but this will open a window that lists all of the software you have installed, including the version of each. I think I remember that older operating systems than Catalina will also reflect which applications are 32 bit or 64 bit. If that is correct, then you will know which apps need to be upgraded. Some upgrades, if needed, such as Microsoft Office will have an up front cost.

I have one old iMac running High Sierra It's good and it's stable. Very likely, with the release of the next OS, Apple will discontinue support of High Sierra. It will still be a good and stable OS. I have Catalina on two other computers and It is a very good and also stable OS*.The key thing to know is that with Catalina, none of your older 32 bit apps will function and will have to be updated or upgraded to 64 bit apps at a cost to you. Catalina is the most secure OS ever offered. The hard drive is separated into two sections: Macintosh HD and Macintosh HD - Data. The first section is where all of the Apple installed apps and files are placed. It is read only, so there is no way it can be messed with or infected with any virus. This is big. The second section is where all of our files and apps are installed. The same concept is carried forward in Big Sur, which is the next OS to be released. Have you verified that your computer can be upgraded to Catalina?

*I am adding this because there have been users on this forum who have bitterly complained that Catalina ruined their computers and blamed Apple for releasing junk. This is absolutely untrue. Ultimately, in every case, there were other reasons for their problems. It's just that the underlying problem(s) manifested when they upgraded their OS. The problems were often due to having installed incompatible junk apps, or having done a download which got corrupted, or in failing to do proper maintenance to keep their OS healthy. Ultimately, with corrective actions, the problems were resolved.

Here is what Catalina offers:

macOS Catalina - Apple

I have been using the Big Sur beta for several months and upgraded to the Big Sur regular release the day before it was released and I can say I really like it. Many improvements. I say go for it.